1. Field of the Invention
The present invention relates to a surgical stapling and cutting instrument adapted for use in the diagnosis and therapy of pathologies treated by stapled resection. More particularly, the invention relates to a cartridge module for surgical stapling and cutting instruments that includes detents for the driver and knife assemblies.
2. Description of the Prior Art
Surgical stapling and cutting instruments are commonly utilized in the diagnosis and treatment of pathologies treated by stapled resection. Surgical stapling and cutting instruments provide a mechanism to extend the transluminal exploitation of mechanical suturing devices introduced via the anal canal, mouth, stomach and service accesses. Although surgical stapling and cutting instruments are most commonly utilized with rectal pathologies, surgical stapling and cutting instruments may be used in a variety of environments.
Over time, surgical stapling and cutting instruments have been developed. These instruments generally include a support frame, an anvil attached to the support frame and a cartridge housing carrying a plurality of staples. The instruments also include a driver within the cartridge housing which pushes all of the staples out simultaneously into the anvil to form the staples into a generally B-shape, suturing tissue together. In addition, these instruments include approximation mechanisms for moving the cartridge housing from a spaced position from the anvil to accept tissue therebetween to a closed position where the tissue is clamped between the anvil and the cartridge housing. Finally, the devices include a firing means for moving the driver forward to form the staples against the anvil.
Many of these instruments rely upon replaceable cartridge modules including a plurality of staples. These replaceable cartridges permit multiple usage of surgical stapling and cutting instruments by simply replacing the cartridge modules after each staple procedure. Most cartridge modules include a staple driver and a knife assembly. Both assemblies slide within the cartridge housing when the device is fired. Prior to use, the staple driver assembly and the knife assembly must be held in a retracted position within the cartridge module. The structure holding the staple driver assembly and knife assembly in this position must be strong enough to prevent movement during shipping. Movement of the staples out of their pockets may lead to staples falling out or being out of position, both of which may lead to bleeding staple lines or worse. Movement of the knife assembly to a position where the knife is exposed might cause injury to anyone using the device or an inadvertent cut in tissue during use on a patient.
After firing of the cartridge module, the staple driver assembly must remain in its forward fired position. The stapler driver assembly is retained in this position to ensure that the spent cartridge lockout assembly is activated. The staple driver assembly is also retained in this position such that the driver tips remain visible providing the user with a visible clue that the cartridge module is spent.
The knife assembly must be retracted and held within the cartridge housing after the device is fired and the trigger is released. The structure that holds the knife assembly in the retracted position must withstand the forces experienced during reloading so that the knife cutting edge is not exposed.
Since the cartridge module may be fired several times during manufacturing, the structures that hold the driver assembly and the knife assembly within the cartridge module must be durable enough to withstand repeated cycling. The force required to reset the staple driver assembly and the knife assembly to the retracted positions should also be minimized to ease manufacturing and to minimize the knife retraction force requirement (spring force) for the instrument.
With this in mind, an improved cartridge module providing structure for holding and indicating the position of the staple driver assembly and the knife assembly is required. The present invention provides such a cartridge module.